Updated Norwegian translations in preparation for v3.0

For all you Norwegians out there!

Signed-off-by: Henrik Brautaset Aronsen <subsurface@henrik.synth.no>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
planner.c: Use g_time_zone_find_interval()

current_time_notz():
Attempt to use g_time_zone_find_interval() to retrieve a
timezone interval, which is then passed to g_time_zone_get_offset()

Reported and tested-by: Sergey Starosek <sergey.starosek@gmail.com>
Signed-off-by: Lubomir I. Ivanov <neolit123@gmail.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Add 'Save As' entry to context menu shown when right clicking on a dive

Something which is nice especially when asked on the list to share an
interesting dive is the possibility to save just some dives into a file.

This commit adds to the context menu shown with right-click the 'Save As'
entry. This entry allows to save selected dives.

[Dirk Hohndel: clean up white space, commit message and remove unused
               variables]

Signed-off-by: Pierre-Yves Chibon <pingou@pingoured.fr>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>